Orthopedic components are well known in the art.
For example, in joint replacement surgery, portions of a joint are replaced with orthopedic components so as to provide long-lasting function and pain-free mobility. More particularly, in the case of a prosthetic total hip joint, the head of the femur is replaced with a prosthetic femoral stem component, and the socket of the acetabulum is replaced by a prosthetic acetabular cup component, whereby to provide a prosthetic total hip joint. Similarly, in the case of a prosthetic total knee joint, the top of the tibia is replaced by a prosthetic tibial component, and the bottom of the femur is replaced by a prosthetic femoral component, whereby to provide a prosthetic total knee joint.
Orthopedic components are also used in a variety of other ways. For example, orthopedic components may be used to stabilize a fractured bone, or to secure two vertebral bodies together, or to hold a bone graft to a bone, or to secure soft tissue to a bone, etc.
In many situations, an orthopedic component may comprise two or more elements which may need to be secured to one another. By way of example, in the case of a prosthetic total hip joint, the prosthetic femoral stem component is sometimes constructed out of a plurality of separate elements, wherein each of the elements may be independently selected so as to most closely approximate patient anatomy, and wherein the separate elements may be assembled to one another using modular connections, so as to provide the best possible prosthetic femoral stem component for the patient. Similarly, in the case of a prosthetic total knee joint, the prosthetic tibial component is also sometimes formed out of a plurality of separate elements which are assembled using modular connections. Still other types of orthopedic components may require, or may benefit from, the assembly of a plurality of separate elements using modular connections.
Once deployed in the patient's body, the orthopedic components, and hence the modular connections securing the separate elements to one another, are typically subjected to axial, bending and torsional loads. While different types of modular connections are known in the art, no one type of existing modular connection is ideal for dealing with all three types of loads, i.e., axial, bending and torsional loads. By way of example, taper connections generally accommodate axial (i.e., compressive) loads well, but they generally do not accommodate bending and torsional loads particularly well. By way of further example, concentric cylinder connections generally accommodate bending loads well, but they generally do not accommodate axial and torsional loads particularly well.